本文關鍵詞： 淺埋偏壓 小凈距隧道 反壓護拱 數(shù)值模擬 穩(wěn)定性　出處：《長沙理工大學》2015年碩士論文　論文類型：學位論文

【摘要】：隨著我國交通事業(yè)的迅猛發(fā)展和綠色環(huán)保、自然和諧設計理念的廣泛普及,小凈距隧道以其獨特的優(yōu)勢被廣泛應用于山區(qū)公路隧道的修建中。小凈距隧道洞口段地質(zhì)條件惡劣,受埋深淺和地形偏壓的不利因素影響,圍巖自穩(wěn)能力差,開挖后,收斂變形大,成洞困難,容易產(chǎn)生塌方冒頂事故,是隧道施工中的控制性地段。如何采取經(jīng)濟合理的輔助施工措施與開挖方法,在確保施工安全的前提下,減小淺埋和偏壓對隧道穩(wěn)定的不利影響,是淺埋偏壓小凈距隧道在設計和施工中面臨的關鍵問題。本文以溫州市蒼南縣藻溪隧道為工程背景,在參閱大量相關文獻資料的基礎上,針對上述問題進行了系統(tǒng)的分析和研究。(1)詳細總結(jié)了隧道偏壓處治技術(shù)和淺埋隧道的開挖方法。介紹了彈塑性力學理論和Flac~(3D)軟件建模的基礎知識。(2)利用數(shù)值模擬軟件Flac~(3D)研究了反壓護拱對淺埋偏壓小凈距隧道穩(wěn)定性的影響,通過分析不同厚度反壓護拱下隧道圍巖的位移、應力集中系數(shù)和塑性區(qū)的分布情況,得到了Ⅳ級和Ⅴ級圍巖反壓護拱的最優(yōu)厚度,為反壓護拱施工方案的優(yōu)化提供了可靠依據(jù)。(3)對Ⅳ級和Ⅴ級圍巖進行了不同開挖方法的數(shù)值模擬,通過對比隧道最終的穩(wěn)定性,優(yōu)選出了合理的開挖方案。(4)研究了優(yōu)選開挖方案的施工過程,通過分析開挖過程中圍巖關鍵點和中夾巖柱位移的變化情況,圍巖應力集中區(qū)和塑性區(qū)的分布情況,了解隧道在施工過程中的薄弱環(huán)節(jié),為科學指導施工提供依據(jù)。本文立足于學科前沿,采用先進的數(shù)值計算方法與分析手段,對反壓護拱偏壓擋墻的厚度以及隧道開挖方案的優(yōu)化進行了研究,具有較高的工程應用價值,為系統(tǒng)開展淺埋偏壓小凈距隧道的穩(wěn)定性研究提供了一種有效的分析手段。
[Abstract]:With the rapid development of transportation and environmental protection in our country, and the widespread popularization of the concept of natural harmony design, the small clear distance tunnel is widely used in the construction of highway tunnel in mountainous area because of its unique advantages. The geological conditions of the entrance section of the small clear distance tunnel are poor. Affected by the unfavorable factors of buried depth and topographic bias, the self-stability of surrounding rock is poor. After excavation, the convergence deformation is large, the formation of tunnel is difficult, and the caving accident is easy to occur. It is a controlling section in tunnel construction. How to adopt economical and reasonable auxiliary construction measures and excavation methods to reduce the adverse effects of shallow burying and bias pressure on tunnel stability under the premise of ensuring construction safety, This paper takes Chaoxi Tunnel in Cangnan County of Wenzhou City as the engineering background, and on the basis of consulting a large number of related documents, it is the key problem in the design and construction of shallow bias voltage and small clear distance tunnel. This paper makes a systematic analysis and research on the above problems. (1) summarizes in detail the treatment technology of tunnel bias and the excavation method of shallow tunnel, introduces the theory of elastoplastic mechanics and the basic knowledge of software modeling of Flacan 3D), and makes use of numerical simulation. Software Flacan 3D) is used to study the effect of reverse pressure arch on the stability of tunnel with shallow bias voltage and small clear distance. Based on the analysis of the displacement, stress concentration factor and the distribution of plastic zone of the surrounding rock under the tunnel arch with different thickness, the optimum thickness of the 鈪，

本文編號：1507911